Two studies in QCD

Two investigations in quantum chromodynamics are presented. The first, entitled Factorization at low x, is a study in perturbative QCD of high energy hadron-hadron collisions using the double log approximation to probe new, hitherto unstudied, kinematic regions. The reaction proceeds via a parton from hadron one (with a fraction of the hadron's momentum x1, and probability of being in the hadron, F1) colliding with a parton from hadron two (with momentum fraction x2 an structure function F2). The new regions of study are those in which one momentum fraction is much larger than the other (i.e. x1 >> x2, or x2 >> x1). New processes, involving soft gluons, are identified and an estimate for their contribution to the cross-section is given. Although involving soft gluons, it is seen these processes nevertheless preserve factorization as they can be incorporated into a redefinition of one of the structure functions (F2 or F1 respectively). The second study, Gluons in the Chiral Bag, is a perturbative QCD calculation, using cavity quantum chromodynamics, of gluon exchange corrections to the cranking moment of inertia of the chiral bag model (CBM). Cranking (the introduction of a slowly rotating, quantized collective motion) is needed to construct the nucleon and delta states in the CBM. By fitting the empirical Δ - N mass splitting a value of the effective strong coupling is extracted. It is found that when the bag is small (R < 0.5 fm), the nucleon-delta mass splitting is adequately described without including any gluon corrections. For larger bag radii, (i.e. R = 1 fm) the size of the coupling constant (αc = 0.6) thus extraced compares favorably with the MIT coupling (αc = 0.055)t represents no true improvement